Polypharmacy 2 Flashcards
5 common classes of medications that cause admissions
- NSAIDs - GI bleed, renal function
- Antiplatelets
- Anticoagulants
- Diuretics - AKI, electrolyte (low Na+), hypotension –> falls risk
- Antihypertensives
Where do medication errors commonly occur?
- Primary care
- Care homes
- Secondary care - least common - less patients to look after
Where in the journey do prescription errors occur?
- Prescription writing
- Dispensing
- Administration
- Transitions
What do clinical pharmacists do?
- Ward round participation
- Monitoring and reporting ADRs - via yellow book (post marketing surveillance)
- Therapeutic drug monitoring
- Prevention and monitoring drug interactions
- Patient counselling re medications
- Clinical research
What dose of morphine is suggested to then becomes useless for pain?
120mg per day - after this you begin getting more side effects and battle tolerance issues
How to prescribe liquid doses?
- Prescribe dosage - not mls
- As the liquids can come in different strengths
What is bioavailability?
- How much of the drug actual makes it to the blood stream to be able to then act on receptors
- It passes through GI tract and liver prior to this - will affect bioavailability depending on formulation (eg tablet, IV, subcut)
Morphine - oral to SC calculation
- Divide oral dose by 2
- Subcut = double strength of oral
Examples of medicines that should be prescribed by brand
- Anti-epileptics - varies between brands, affects bioavailability, if stable prescribe same again
- Insulin
What is medicine reconciliation
- Three C’s
- Collection - new medications, what they take and what they are prescribed, include OTC and herbal
- Checking - against reliable sources (at least 2)
- Communication
Sources we can use for medicines reconciliation
- Patient or carer
- Patients own medications (PODs) - supply on d/c
- Patients reminder charts - confirm with pt that they are new
- GP repeat prescriptions
- GP surgery/summary care record
- SystemOne - electronic patient record and recent outpatient letters
- Discharge letters or old drug charts if recently discharged after hospital admission
Targets of drugs - where can they act
- Mostly cellular (but not all eg antacid)
- Mostly proteins (either on cell surface or inside cells)
- Mostly receptors (agonists and antagonists)
- But can be ion channels, enzymes and transport proteins
- These are already there biologically, we then use drugs that act on them alongside natural substrate
What is pharmacodynamics?
What the drug does to the body - biochemical, physiological and therapeutic effects of drug
What is pharmacokinetics?
What the body does to the drug
* ADME
* Absorption - absorbed when reach blood, IV does not require (all others do)
* Distribution - movement of drug around body
* Metabolism - destruction of drug by chemical alteration (usually via liver)
* Excretion - removal of drug from body (eg kidneys or bile)
Elimination = metabolism + excretion
How can drug interactions work?
- Pharmacodynamic - Drug A alters action of Drug B - concentation of drug B in tissue fluid is unaltered but effect is altered
- Pharmacokinetic - drug A alters ADME of drug B - concentration of drug B that reaches site of action is altered
